cffi-posix/cffi-unistd

diff --git a/grovel-unistd.lisp b/grovel-unistd.lisp
index fcecb0b..408acce 100644
--- a/grovel-unistd.lisp
+++ b/grovel-unistd.lisp
@@ -18,6 +18,8 @@
 
 (in-package :cffi-unistd)
 
+(include "sys/select.h")
+(include "sys/socket.h")
 (include "unistd.h")
 
 (constant (+stdin-fileno+ "STDIN_FILENO"))